It is common to utilize sprinkler heads in buildings for the purpose of enabling water to be applied automatically to a fire in the building. Most sprinkleer heads incorporate a heat sensitive member formed of eutectic material which liquifies upon reaching a predetermined critical temperature. In most conventional sprinkler head constructions, the eutectic material forms part of a link or strut which normally precludes the discharge of water from the head, but which, upon reaching its predetermined temperature, liquifies and effects collapsing of the link or strut, thereby enabling a value to open and water to be sprayed from the head. Examples of such prior constructions are illustrated in U.S. Pat. Nos. 241,937; 1,315,079; 1,584,719; 2,129,012; and 2,664,956.
One of the difficulties with conventional sprinkler heads is the time required to raise the temperature of the eutectic material to that at which it liquifies. It is not uncommon for the temperature within a building to rise to a level corresponding to or above the critical temperature of the eutectic material and to remain at such elevated temperature for an unduly long period of time before the sprinkler is actuated. This is believed to be due, in large part, to the fact that, in such prior constructions, heat is absorbed not only by the eutectic material, but by all parts of the sprinkler head. Thus, although the ambient temperature is at or higher than the critical temperature, some time is required for the eutectic material to absorb sufficient heat to raise it to its critical temperature. In those instances in which heat must be transmitted via other parts of the sprinkler head to the eutectic material, therefore, the necessity of raising the temperature of such other parts to the critical temperature actually results in a time lag in sprinkler head operation. Such time lag in some cases may mean the difference between losing and saving the building and its contents.